Authorities said the Mount Agung volcanic eruption was expected within hours, not days, given the build-up of magma which is now flowing continuously.

The pair met five years ago when Ms Horch worked as a dental nurse and Mr Steer was her patient. They are now trying to find a local venue in Melbourne so they can still get married on Monday, with a friend setting up a GoFundMe page to assist with last minute preparations.

"Everyone has taken annual leave," she said.

"We don't want to call off the wedding ... we want to try and have everyone we love around us.

"But it's getting the little things like flowers, photographers, hair and make-up in time, so we are seeing if anyone knows anyone who can help us out last minute."

Ms Horch said their travel insurance wasn't able to cover any of their expenses, because they'd purchased their policy after warnings were issued by the Indonesian government.

Currently, tens of thousands of people are now stranded in Bali as Mt Agung spews hot ash, putting a halt to all flights in and out of the holiday island.

Many of those travellers, like Ms Horch, Mr Steer and their guests, are not covered, even if they have travel insurance.

A number of Australian insurers have issued statements saying their customers would only be covered if they had bought insurance policies up to nine weeks ago - before the Indonesian government issued an alert for the volcano.

Some companies have stipulated a cut-off coverage date of September 22, which is when the volcano alert was first raised to a level four, suggesting an eruption was imminent.

Others are refusing to cover those who purchased a policy on or after September 18 when the alert was raised from normal to "vigilance".

The Mount Agung volcano continues to erupt today on Bali, but it remained unclear how bad the eruption might get or how long it could last.

Ms Horch said they aren't in a position to reschedule their wedding in Bali because of annual leave restrictions with their current jobs. The cancelled wedding comes as a second blow to the pair after Mr Steer's mother passed away unexpectedly eight weeks ago.

"She had a lung condition ... we got the call unexpectedly [that she died] so close to our wedding," Ms Horch said.

"We can't get leave from our current jobs at any other time, so we want to do it [in Melbourne] in five days."

On the GoFundMe page, Ms Horch said the pair were shattered that their dream day would not become a reality.

"We are beyond devastated that we have now lost our wedding, our accommodation and our honeymoon but we want to try and make this situation as great as we can," she wrote on the page.

"We have minimal money left and we are hoping there might be some generous businesses or people in the greater public that could band together to help us out."